Buggy code:
public class SummaryStatisticsTest extends TestCase { private double one = 1 ; private float twoF = 2 ; private long twoL = 2 ; private int three = 3 ; private double mean = 2 ; private double sumSq = 18 ; private double sum = 8 ; private double var = 0.6666666666666666 ; private double std = Math . sqrt ( var ) ; private double n = 4 ; private double min = 1 ; private double max = 3 ; private double tolerance = 1.0E-14 ; public static Test suite ( ) { } public SummaryStatisticsTest ( String name ) { } protected SummaryStatistics createSummaryStatistics ( ) { } public void testStats ( ) { } public void testN0andN1Conditions ( ) throws Exception { } public void testProductAndGeometricMean ( ) throws Exception { } public void testNaNContracts ( ) { } public void testGetSummary ( ) { } public void testSerialization ( ) { } public void testEqualsAndHashCode ( ) { SummaryStatistics u = createSummaryStatistics ( ) ; SummaryStatistics t = null ; int emptyHash = u . hashCode ( ) ; assertTrue ( "reflexive" , u . equals ( u ) ) ; assertFalse ( "non-null<seq2seq4repair_space>compared<seq2seq4repair_space>to<seq2seq4repair_space>null" , u . equals ( t ) ) ; <START_BUG> assertFalse ( "wrong<seq2seq4repair_space>type" , u . equals ( new Double ( 0 ) ) ) ; <END_BUG> t = createSummaryStatistics ( ) ; assertTrue ( "empty<seq2seq4repair_space>instances<seq2seq4repair_space>should<seq2seq4repair_space>be<seq2seq4repair_space>equal" , t . equals ( u ) ) ; assertTrue ( "empty<seq2seq4repair_space>instances<seq2seq4repair_space>should<seq2seq4repair_space>be<seq2seq4repair_space>equal" , u . equals ( t ) ) ; assertEquals ( "empty<seq2seq4repair_space>hash<seq2seq4repair_space>code" , emptyHash , t . hashCode ( ) ) ; u . addValue ( 2.0 ) ; u . addValue ( 1.0 ) ; u . addValue ( 3.0 ) ; u . addValue ( 4.0 ) ; assertFalse ( "different<seq2seq4repair_space>n's<seq2seq4repair_space>should<seq2seq4repair_space>make<seq2seq4repair_space>instances<seq2seq4repair_space>not<seq2seq4repair_space>equal" , t . equals ( u ) ) ; assertFalse ( "different<seq2seq4repair_space>n's<seq2seq4repair_space>should<seq2seq4repair_space>make<seq2seq4repair_space>instances<seq2seq4repair_space>not<seq2seq4repair_space>equal" , u . equals ( t ) ) ; assertTrue ( "different<seq2seq4repair_space>n's<seq2seq4repair_space>should<seq2seq4repair_space>make<seq2seq4repair_space>hashcodes<seq2seq4repair_space>different" , ( ( u . hashCode ( ) ) != ( t . hashCode ( ) ) ) ) ; t . addValue ( 2.0 ) ; t . addValue ( 1.0 ) ; t . addValue ( 3.0 ) ; t . addValue ( 4.0 ) ; assertTrue ( "summaries<seq2seq4repair_space>based<seq2seq4repair_space>on<seq2seq4repair_space>same<seq2seq4repair_space>data<seq2seq4repair_space>should<seq2seq4repair_space>be<seq2seq4repair_space>equal" , t . equals ( u ) ) ; assertTrue ( "summaries<seq2seq4repair_space>based<seq2seq4repair_space>on<seq2seq4repair_space>same<seq2seq4repair_space>data<seq2seq4repair_space>should<seq2seq4repair_space>be<seq2seq4repair_space>equal" , u . equals ( t ) ) ; assertEquals ( "summaries<seq2seq4repair_space>based<seq2seq4repair_space>on<seq2seq4repair_space>same<seq2seq4repair_space>data<seq2seq4repair_space>should<seq2seq4repair_space>have<seq2seq4repair_space>same<seq2seq4repair_space>hashcodes" , u . hashCode ( ) , t . hashCode ( ) ) ; u . clear ( ) ; t . clear ( ) ; assertTrue ( "empty<seq2seq4repair_space>instances<seq2seq4repair_space>should<seq2seq4repair_space>be<seq2seq4repair_space>equal" , t . equals ( u ) ) ; assertTrue ( "empty<seq2seq4repair_space>instances<seq2seq4repair_space>should<seq2seq4repair_space>be<seq2seq4repair_space>equal" , u . equals ( t ) ) ; assertEquals ( "empty<seq2seq4repair_space>hash<seq2seq4repair_space>code" , emptyHash , t . hashCode ( ) ) ; assertEquals ( "empty<seq2seq4repair_space>hash<seq2seq4repair_space>code" , emptyHash , u . hashCode ( ) ) ; } private void verifySummary ( SummaryStatistics u , StatisticalSummary s ) { } public void testSetterInjection ( ) throws Exception { } public void testSetterIllegalState ( ) throws Exception { } }

Fix:
assertFalse ( "wrong<seq2seq4repair_space>type" , u . equals ( Double . valueOf ( 0 ) ) ) ;